Fortifications of Brussels

There were two stages of fortifications of Brussels, the first walls, built in the early 13th century, and the second walls, built in the late 14th century and later upgraded. Today, only a few sections of either remain.

The first walls of Brussels (Dutch: eerste stadsomwalling, French: première enceinte) were a series of fortifications erected around the Belgian city of Brussels in the early 13th century. The city quickly outgrew them, and starting in 1356, a second, larger set of walls was built to better enclose and defend the city. The now superfluous walls were dismantled between the 16th to 18th centuries. Isolated portions of the first walls can still be seen today.

Construction on the first walls of Brussels is estimated to have been at the beginning of the 13th century, under the reign of Henry I, the first duke of Brabant. The beginning and end dates are not clear, but construction would have lasted several decades. On the other hand, from historical maps and other documents that have been preserved, the precise former course of the walls is known.

The walls were 4 kilometres (2.5 mi) long. In the west, they encompassed the site of the city's founding and first development, Saint-Géry Island, the Grand Place and the first port on the Senne river. They extended to the heights in the east of the city, enclosing the first St. Michael and St. Gudula Cathedral (then a collegiate church) on Treurenberg hill and the ducal palace of Coudenberg.

The walls were initially made of earth, with a wooden fence on top. These gave way to walls made of stone that were 10 metres (33 ft) tall and 1 to 2.5 metres (3 to 8 ft) thick. The walls were supported by square pillars, spaced roughly 4 metres (13 ft) apart, linked by a row of arches for support. These were buried underneath a talus, and they supported the main wall, which had a number of arrow slits in it. A second arcade supported a crenellated parapet, where defenders could stand. A large ditch was dug in front of the walls, and in places this could be flooded with water to form a moat if needed. Along the length of the walls, there were roughly 40 defensive towers, in addition to seven primary gates and five smaller entrances.

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